On 03/21/2018 01:56 PM, Andrew Morton wrote: > On Wed, 21 Mar 2018 09:13:14 -0700 Mike Kravetz <[email protected]> > wrote: >> >> +static int shm_split(struct vm_area_struct *vma, unsigned long addr) >> +{ >> + struct file *file = vma->vm_file; >> + struct shm_file_data *sfd = shm_file_data(file); >> + >> + if (sfd->vm_ops && sfd->vm_ops->split) >> + return sfd->vm_ops->split(vma, addr); > > This will be the only site which tests for NULL shm_file_data.vm_ops. > It's a can't-happen, methinks.
You are correct, thanks for catching this. > > I think I'll leave it as it is for now and will queue up a non-urgent > patch: > > > > From: Andrew Morton <[email protected]> > Subject: ipc/shm.c: shm_split(): remove unneeded test for NULL > shm_file_data.vm_ops > > This was added by the recent "ipc/shm.c: add split function to > shm_vm_ops", but it is not necessary. > > Cc: Laurent Dufour <[email protected]> > Cc: Dan Williams <[email protected]> > Cc: Michal Hocko <[email protected]> > Cc: Davidlohr Bueso <[email protected]> > Cc: Manfred Spraul <[email protected]> > Signed-off-by: Andrew Morton <[email protected]> Looks good, FWIW Reviewed-by: Mike Kravetz <[email protected]> -- Mike Kravetz > --- > > ipc/shm.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff -puN > ipc/shm.c~ipc-shmc-shm_split-remove-unneeded-test-for-null-shm_file_datavm_ops > ipc/shm.c > --- > a/ipc/shm.c~ipc-shmc-shm_split-remove-unneeded-test-for-null-shm_file_datavm_ops > +++ a/ipc/shm.c > @@ -391,7 +391,7 @@ static int shm_split(struct vm_area_stru > struct file *file = vma->vm_file; > struct shm_file_data *sfd = shm_file_data(file); > > - if (sfd->vm_ops && sfd->vm_ops->split) > + if (sfd->vm_ops->split) > return sfd->vm_ops->split(vma, addr); > > return 0; > _ >
